Unfortunately fix for TOUCH-4126introduced additional problems, making behavior of Ext.DomQuery.is in some cases extremely destructive.

Following things do not work:

passing element id will result in that element being removed from DOM

checking elements outside DOM is still broken in some cases

function do not support Array as first argument as specified in documentation

Here comes my fiddle illustrating all these problems and tests for them

Also this fiddle includes fix for all of them: first two are errors in code - we shouldn't query parentNode before we convert el from string to element and we should pass root to this.select if we have any

Last one was implemented on my own, trying to keep code close to framework style